20.1 ocean water properties (physical….) (…and chemical.)
TRANSCRIPT
20.1 Ocean Water Properties
(physical….)(…and chemical.)
Composition of Ocean water
• 96.5% pure water
• Dissolved solids (salts)- Cl , Na, Mg, S, Ca, K- mostly from river runoff
• Dissolved gases-N2, O2, CO2
- From river runoff, atmosphere and undersea volcanoes
- Polar areas have more dissolved gas than tropical areas
Salinity
The amount of dissolved solids in a liquid
Measured in parts per thousand; # of grams of the solid in 1 kg of H2O
Ocean water is 35 parts per thousand salt or 3.5% salt
Factors Affecting SalinityFreezing Increases Water freezes leaving salt
behindPrecipitation Decreases Dilutes surface water
(Tropics)
Evaporation Increase Water evaporates leaving salt behind (Equator)
River Runoff Decrease Dilutes surface water
Depth Increase Evaporation at surface makes in salty at top and less as you go deeper
The RED SEA
The BALTIC SEA!
Hot…High evap rate… SALTY!!
Cool…low evap rate, lots of runoff… NOT SALTY!!
Verses
OCEAN WATER TEMPERATURE
* the IR rays of the SUN heat the ocean waters.* the mixing effect distributes the solar heat down to 300 m.
Tropics surface temp @ 30o CPolar surface temps @ -2o C(pack ice
forms…)Middle lattitudes, surface temps vary
Thermocline
• Zone of rapid temp. change
• Caused by warm/cold barrier
• Waters can’t mix due to differences in density
Density
Affected by salinity and temperature
Cold = more dense
Warm = less dense
Densest water in polar regions
Color
• Ocean water appears blue because only blue light is reflected. The other colors are absorbed.
• Appears blue down to 100m.
• If you go deeper it is black